Lightning-arrester



(No Model.)

1E. G. Wij C. HOFFMANN.

LIGHTNING ARRESTER.

Patented Jan. 28, 1896.

NlA PHOTO-UTN QWASHIN GTG UNITED STATES PATENT OFFICE.

ERNST GUSTAV IVILI'IELM CARL HOFFMANN, OF CHARLOTTENBURG,GER MANY,ASSIGNOR TO THE SIEMENS du HALSKE ELECTRIC COMPANY OF AMERICA, OFCHICAGO, ILLINOIS.

LIGHTNING-ARRESTER.

SPECIFICATION forming part of Letters Patent No. 553,528, dated January28, 1896.

Application led September 3, 1895. Serial No. 561,221. (No model.)

To all whom t may concern:

Beit known that I, ERNST GUsTAv WIL- HELM CARL HOFFMANN, a subject ofthe Emperor of Germany, residing at Charlottenburg, near Berlin,Germany, have invented new and useful Improvements in Lightning-Arresters with Arc-Extinguishing Devices, (Case No. 629,) of which thefollowing is a specification.

This invention relates to an improved combined lightning-arresting andarc-eXtin guishing device for use with electric conductors, and has forits object to provide a simple, inexpensive, automatic and efficientdevice of this character which will prevent injury to the dynamo orother electrical apparatus, while avoiding short-circuiting of thecurrent throughthe earth when the conductor or conductors are struck bylightning.

Reference is to be had to the accompanying drawings, forming part ofthis specification, in which- Figure l is a central vertical sectionalelevation of the lightning-arresting and arc-extinguisher device and aportion of the line conductor. Fig. 2 is a View taken at right angles toFig. l,.with the casingindicated by dotted lines; and Figs. 3 and 4. areillustrative diagrams hereinafter referred to.

Like letters refer to like parts in the several figures.

The base portion a of the device is made of any suitable non-conductiveor insulating material and is held by a bracket b to a crossbar or postor other support c. The line-Wire or electric conductor d is suitablyheld in the lower hook end of a metal rod a', which passes through theinsulated base a, and at its upper end is electrically connected withthe lower metal plate, e', of a primary arrester device e, which restson the base a. The upper metal plate, e2, of this arrester e is fastenedto the lower end of a metal rod f, which at its upper end carries ashouldered head f which by resting on the bottom of the hollowconductive core g, within which said head f may move, sustains thearrester-plate e2 at proper normal distance above the opposing plate e.The core g is supported by a vskeleton frame a2 from the base a, andaround it is wound the wire g', thus making a solenoidal magnet of usualform capable of attracting and drawing upward the rod f f and plate e2of the arrester e, as hereinafter described.

From one end, g2 of the coil g' a wire g3 extends to the upper fixedplate, 7d, of another and secondary arrester device h, the lower fixedplate, h2, of which is connected by a wire g4 with the other end, g5,ofthe solenoid-coil g@ whence a wire 7c extends to a suitable ground orearth plate k. Between the plates h h2 of the arrester h is preferablyplaced a small fusible conductive body I to facilitate passage oflightning across the space between the plates. .The two opposing platesof the arresters e 7i are preferably serrated, asis usual with devicesof this character. A suitable inverted-cup casing m supported on theinsulated base a protects the parts from rain or snow or adverse weatherinfluences. 7o

In order to more clearly explain the operation of my invention, Iproduce by way of comparison the illustrative diagram, Fig. 3,whichindicates supply and return conductors n n', connected to a dynamo o andgrounded by wires n2 n3 and corresponding earth-plates n4, saidground-wires having ordinary two-plate lightning-arresters p r,respectively. In this instance, should lightning strike one of theconductors-say the line n-it would pass 8o through or across arrester pto ground, and should the plates of the arrester be melted together bythe stroke, and should there happen to be a slight ground connection, aconstant loss of current of or from the dynamo would result.

Should lightning strike both lines n a simultaneously, it Would jump byheavy light arcs across between the plates of the two arresters p r tothe earth connections and shortcircuit the line through the dynamo andinjure the machine, the current in this case being along line n, acrossarrester p, on Wire n2, through the earth and ground connections n, wirea3, arrester r, and along wire n' to the dynamo. Should there be but onesupplyconductor having a two-plate lightning-arrester, and the return bemade through the earth, as in electric-railway systems, lightningstriking the conductor would short-cir- IOO cuit the current through thedynamo and cut out the main line,while injuring the machine.

The diagram Fig. l illustrates the application of my invention when theline-wire (Z is a supply-conductor and the return to the dynamo isthrough the earth. lt will be understood, however, that when two wiresare used for supply and return conductors, as in Fig. 3, the arresterdevices are applied to both conductors.

Referring new to Fig. i and also to Fig. l of the drawings, it will beseen that should lightning strike the line-wire d it will pass throughthe hanger ce and across between the plates e c2 of arrester c, andthrough the rod 7 to conductive core g, thence to connect-ion g2 andwire g3, and through the plates 71,/ h2 and interposed fusible metal lof arrester 7i, and thence by wire g" to connection yf, and by wire 7cto ground. Only a very small part of the static lightning-discharge willpass into or through the solenoid-coil g', due to its resistance, andthe rod j j' will not be drawn upward within the core g. A heavy currentfrom the dynamo fra line d and following the lightning will, however,traverse the solenoid-coil and energize its core g sufficiently to drawupward the rod f j, and also the connected pla-te e2, and thus separatethe plates e' e2 of arrester e sufficiently to automatically extinguishthe are between it wholly and normally to the line-wire (l withoutinjury to the arrester devices or the dynamo-machine. Immediately thearc is extinguished at the arrester e, the solenoid loses itsattraction, and the upper plate, e2, of this arrester falls, and theparts are restored to normal relative poA sitions, (shown in Fig. l ofthe drawings,) ready for the next lightning-stroke of the line-wire.

The fusible body 7, which had facilitated passage of the static currentthrough the opposing plates 71/ h2 of arrester 7L, will be melted by thelightning, thus leaving an open space between the plates, ready for thenext static discharge, and indicating bythe melting olf said body Z thatthe apparatus has been struck by lightning.

I claim as my inventionl. A lightning arrester for electric eondui tors,comprising primary and secondz'u'y arrester devices in circuit betweenthe conductor and the earth, and a solenoid magnet interposed in circuitwith the two arrester devices and controlling the are of the primaryarrester device; the secondary arrester haring a fusible body interposedbetween its opposing plates or portions to facilitate the passage of theelectrical. discharge, substantially as described.

2. The combination, in a lightning arrester for electric conductors, oi'an insulated base a, a line wire support as a held thereby and carryinga plate c', a support a? on the base u, a conductive core g/ andsolenoidal wire coil g thereon, sustained by the support a?, a rod j, fheld by core ,l/ and carryinga plate ci", said opposed plates e, e2forming a primary arrester e; wires y, Q connected with oppo site endsof coil g', a secondary arrester 71, comprising opposing plates 71,, h2in circuit with wires g3, g", and a ground connection l.' from thejunction g5 of the, coil g and wire g, substantially as described.

In testimony whereof I have affixed my signature in the presence of twowitnesses.

Vl'lllNf'l GL'STM' ll'lhlllllllll CARL lltWlltiNN.

lVitnesses:

OSCAR KIELEFELD, JOHN B. JACKSON.

